Riot Stance on Custom Skin Mods

This has probably been brought up before, but as a sanity check, Riot's generally okay with map skins and custom skins being used since it's all client-side, right? I believe it was an "Use at your own risk" kind of thing, but you likely wouldn't get banned for it, right?

Specifically, I'm thinking about the stuff you can get from this website http://mapskins.com/ , especially the Frozen Rift map skin.